Since 1990, the annual rate of breast cancer death has been decreasing by approximately 2.2% per year (1). Historically, median survival of patients with metastatic breast cancer (MBC) was estimated to be 18–30 months. Many experts agree that median survival has improved in recent years beyond 30 months, although survival varies significantly by breast cancer subtype. A number of newer active agents have recently been added to the armamentarium against breast cancer, including third-generation aromatase inhibitors, novel antimicrotubule chemotherapy agents, and biologic agents such as lapatinib, pertuzumab, and everolimus. Despite these advances, breast cancer remains the second leading cause of cancer death in women in the United States, with 39,620 women estimated to die of breast cancer in 2013 (1).
Several factors contribute to predicting an individual patient's course of disease:
Prolonged relapse-free survival of more than 5 years is more favorable.
Isolated chest wall or ipsilateral nodal recurrence predicts better outcome than visceral disease.
Bone and soft-tissue recurrence is more favorable than visceral or central nervous system disease.
The prognosis of HER2-positive MBC is not established but median survival may be well beyond 3 years with the advent of newer HER2-directed strategies (2, 3).
The prognosis of triple negative breast cancer (ER/PR/HER2 negative) remains poor with median survival of approximately 1 year (4).
A prognostic index predicts median overall survival of 50, 23, and 11 months for low-, intermediate-, and high-risk groups, respectively (Figure 60-1) (5). However, its utility is limited in clinical practice because it does not account for differences in breast cancer subtypes that impact treatment options.
Up to 2%–3% of patients with favorable characteristics may be long-term survivors with over 20-year survival. Such patients tend to be young, have limited disease, and have a complete response to initial therapy.
Prognostic index for patients with metastatic breast cancer. Patients with MBC were stratified into risk groups based on the total sum of individual prognostic factors as follows: (1) adjuvant chemotherapy—add 1 point if received; (2) distant lymph node metastates—add 1 point if present; (3) liver metastases—add 1 point if present; (4) lactate dehydrogenase—add 1 point if >1× normal; (5) disease-free interval—add 2 points if <24 months. Low-risk group ≤1 point, intermediate group = 2–3 points, high risk ≥4 points. (Adapted from Reference 5 with permission.)
Metastatic breast cancer is not considered curable. Therefore, the goals of treatment must carefully balance the risks of treatment-induced toxicity with the expected clinical benefit. Accepted clinical endpoints in the treatment of MBC include prolonged overall survival, improved quality of life (QOL), progression-free survival (PFS), and cancer-related symptom control.
Most patients with MBC present with a recurrence following treatment for early-stage ...